Question

For each of the following single strands of DNA, write the correct DNA counterstrand using the rules of Watson-Crick DNA structure. To get the correct answer, your final structure must have:

i) Antiparallel strands

ii) Watson-Crick base pairs at each position

1. 5’-GCTGCATCCGTTAA

2. 3’-ATGGCTACTACGTA

3. TCGAATCCAGCTAGGC-5’

Answer 1

Q) For each of the following single strands of DNA, write the correct DNA counter strand using the rules of Watson-Crick DNA structure. To get the correct answer, your final structure must have:

i) Antiparallel strands ii) Watson-Crick base pairs at each position

1. 5’-GCTGCATCCGTTAA

2. 3’-ATGGCTACTACGTA

3. TCGAATCCAGCTAGGC-5’

Ans) Double helical model of DNA was given by the James Watson and Francis Crick in 1953 based on the Chargoff’s rules and X-ray diffraction data of Wilkins and Franklins. According to them, two polynucleotide chains run twist around each other form right-handed double helix. They are anti-parallel in nature (one strand run in 5’ to 3’ direction and other in 3’ to 5’ direction). In DNA Adenine always pair with Thymine with two hydrogen bonds and Guanine always pair with Cytosine with three hydrogen bonds.

5’-GCTGCATCCGTTAA-3’

3’-CGACGTAGGCAATT-5’

3’-ATGGCTACTACGTA-5’

    5’-TACCGATGATGCAT-3’

3’-TCGAATCCAGCTAGGC-5’

5’-AGCTTAGGTCGATCCG-3’